1. Field of the Invention
This invention relates to refrigerated chambers or buildings and more particularly to means for preventing the inflow of warm outside air into the upper portion of the structure.
2. Description of the Prior Art
It has long been recognized that there is air movement through the insulated walls in refrigeration buildings when the outside temperature is greater than the inside temperature. This is due in a considerable degree to the increased density of the cold air which tends to sink to the floor, whereby the air pressure at the bottom is greater than outside pressure and the air pressure at the top, near the ceiling, is less than the external pressure. Thus, air tends to flow in through the walls and ceiling at the top and to flow out at the bottom. The inward flow of warm outside air is harmful in that moisture condenses within the walls and causes deterioration of the insulation and wall structure.
It has been proposed by Ophuls, U.S. Pat. No. 1,947,223, to avoid these problems by maintaining the pressure within a refrigerating building somewhat higher than the external pressure, whereby there would be an air flow of cold air outwardly through the walls. He also suggests a false wall around the entire insulating wall structure with a space therebetween and maintaining a subatmospheric pressure in the intermediate space. This solution involves extensive structural additions with attendent increase in cost, which my invention, which makes use of generally already existing structural features, avoids.